1cfl
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(New page: 200px<br /><applet load="1cfl" size="450" color="white" frame="true" align="right" spinBox="true" caption="1cfl" /> '''DNA DECAMER DUPLEX CONTAINING T5-T6 PHOTOADD...)
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Revision as of 23:20, 24 November 2007
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DNA DECAMER DUPLEX CONTAINING T5-T6 PHOTOADDUCT
Overview
The pyrimidine(6-4)pyrimidone photoproduct [(6-4) adduct] is one of the, major photoproducts induced by UV irradiation of DNA and occurs at TpT, sites. The (6-4) adduct is highly mutagenic and leads most often to a 3' T, --> C transition with 85% replicating error frequency [LeClerc, J. E., Borden, A. & Lawrence, C. W. (1991) Proc. Natl. Acad. Sci. USA 88, 9685-9689]. To determine the origin of the specific 3' T --> C transition, of the (6-4) adduct, we have used experimental NMR restraints and, molecular dynamics to determine the solution structure of a (6-4)-lesion, DNA decamer duplex that contains a mismatched base pair between the 3' T, residue and an opposed G residue. Normal Watson-Crick-type hydrogen, bonding is retained at the 5' T of the lesion site. The O2 carbonyl of the, 3' T residue forms hydrogen bonds with the imino and amino protons of the, opposed G residue. This potential hydrogen bonding stabilizes the overall, helix and restores the highly distorted conformation of the (6-4) adduct, to the typical B-form-like DNA structure. This structural feature can, explain the marked preference for the insertion of an A residue opposite, the 5' T and a G residue opposite the 3' T of the (6-4) lesion during, trans-lesion synthesis. Thus these insertions yield the predominant 3' T, --> C transition.
About this Structure
1CFL is a Protein complex structure of sequences from [1]. Full crystallographic information is available from OCA.
Reference
Solution structure of a DNA decamer duplex containing the stable 3' T.G base pair of the pyrimidine(6-4)pyrimidone photoproduct [(6-4) adduct]: implications for the highly specific 3' T --> C transition of the (6-4) adduct., Lee JH, Hwang GS, Choi BS, Proc Natl Acad Sci U S A. 1999 Jun 8;96(12):6632-6. PMID:10359763
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